IR human body recognition

Thread Starter


Joined Mar 2, 2007
Hi all!
I am a student and as a final project me and my partner are trying to construct a robot which orients in space using ultrasonic sensor and is able to recognize a human with infrared detector.
The question is - where to look for info on this (IR) type of detection? Maybe somebody here dealt with this kind of problem? Which parts to use, how to approach, etc. Any help is appreciated.


Joined Apr 20, 2004
Interesting project. The human body is a diffuse source of IR, as are things like heating ducts, televisions, and ovens on the other side of the wall. Might have some fun with dogs and cats. too.

Why does the robot have to orient to anything, and what will it do once it has chosen an IR source?


Joined Apr 20, 2004
What sort of algorithm are you going to use? I guess you can look at ambient temperature, and then look for some source either warmer of colder, but how do you decide it's human based on temperature?


Joined Jan 28, 2005
I googled for more information and I did not get anything helpful.

It does seem that this is going to require some sort of differential measurement such as beenthere eluding to. It may need to be combined with some movement sensing.

Interesting project but not an enviable design challenge.



Joined May 16, 2005
PIR triggers on movement. Empty office chairs rolling across the floor will trigger them. (Amazing how bored one can get on swing-shift.)

If people are the only things in the room warmer than the air, then any old IR detector and a comparator should work (with enough tweaking). If there are also TV sets, computers, rottweilers, and such, then something more sophisticated or sensitive will be needed.

Tube Tech

Joined Jan 11, 2007
A suggestion that will cost some money and time, but help you a lot:

Get a DVR card from eBay. About $20. Acquire a video camera to feed it with.

Download this software:

Free download. They expect you to pay for it after a month, but you won't be using it for its intended purpose, and it will still work.

Follow these instructions:

Set the sensitivity high, 95 - 97%.

Set the software to show motion.

What you will see: dozens of individual pixels light up green for no obvious reason. Moths show up as green balls. Cats, dogs, fuzzy horizontal blobs.

Humans: big fuzzy vertical blobs. The trick to recognizing humans, and only humans, would be to program the system to react only to big vertical blobs.

This assumes that you, or some other reader working on a similar project, will have a PC controlling your project.


Joined May 16, 2005
Would not a cat be a big vertical blob if close enough? (We're talking robot here, POV about cat high.) And would not a human far enough away be a small vertical blob?